All things must be examined, debated, investigated without exception and without regard for anyone's feelings... We must run roughshod over all these ancient puerilities, overturn the barriers that reason never erected, give back to the arts and sciences the liberty that is so precious to them.

It seems to me that if one had kept silence up to now regarding religion, people would still be submerged in the most grotesque and dangerous superstition ... regarding government, we would still be groaning under the bonds of feudal government ... regarding morals, we would still be having to learn what is virtue and what is vice. To forbid all these discussions, the only ones worthy of occupying a good mind, is to perpetuate the reign of ignorance and barbarism.

I have not the hope of being immortal, because the desire of it has not given me that vanity.

My ideas are my whores.

The first promise exchanged by two beings of flesh was at the foot of a rock that was crumbling into dust; they took as witness for their constancy a sky that is not the same for a single instant; everything changed in them and around them, and they believed their hearts free of vicissitudes. O children! always children!

The enjoyment of freedom which could be exercised without any motivation would be the real hallmark of a maniac.

How old the world is! I walk between two eternities.... What is my fleeting existence in comparison with that decaying rock, that valley digging its channel ever deeper, that forest that is tottering and those great masses above my head about to fall? I see the marble of tombs crumbling into dust; and yet I don't want to die!